I'm a newbie for sql server, but I did the installation yesterday. After several errors from a .net application another pc in the home group, a list box is populated. The listbox data is retrieved from a sql server database.
I had to configure windows firewall advanced settings to let sqlserver.exe pass through Click Here .
I dissabled sql server express services and enabled sql server services, sql server browser (not sure if this last one is necesary) and protocols (Click Here)
Lastly, I remember to enable both windows and sql server authentications (https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/change-server-authentication-mode).
So, after all that the connection string became for me: